Perfusion entails encouraging physiological solutions such as blood through the vessels of the body or a portion of a body of a human or animal. Illustrative examples of situations that may employ perfusion include extracorporeal circulation during cardiopulmonary bypass surgery as well as other surgeries. In some instances, perfusion may be useful in providing extracorporeal circulation during various therapeutic treatments. Perfusion may be useful in maintaining the viability of body parts such as specific organs or limbs, either while the particular body part remains within the body, or while the body part is exterior to the body such as for transplantation or if the body part has been temporarily removed to provide access to other body structures. In some instances, perfusion may be used for a short period of time, typically defined as less than about six hours. In some cases, perfusion may be useful for extended periods of time that are greater than about six hours.
In some instances, blood perfusion systems include one or more pumps in an extracorporeal circuit that is interconnected with the vascular system of a patient. Cardiopulmonary bypass (CPB) surgery typically requires a perfusion system that allows for the temporary cessation of the heart by replacing the function of the heart and lungs. This creates a still operating field and allows for the surgical correction of vascular stenosis, valvular disorders, and congenital heart and great vessel defects. In perfusion systems used for cardiopulmonary bypass surgery, an extracorporeal blood circuit is established that includes at least one pump and an oxygenation device to replace the functions of the heart and lungs.
More specifically, in cardiopulmonary bypass procedures, oxygen-poor blood (i.e., venous blood) is gravity-drained or vacuum suctioned from a large vein entering the heart or other veins (e.g., femoral) in the body and is transferred through a venous line in the extracorporeal circuit. The venous blood is pumped to an oxygenator that provides for oxygen transfer to the blood. Oxygen may be introduced into the blood by transfer across a membrane or, less frequently, by bubbling oxygen through the blood. Concurrently, carbon dioxide is removed across the membrane. The oxygenated blood is then returned through an arterial line to the aorta, femoral, or other main artery.